1. Field of the Invention
The present invention relates to a navigation apparatus for vehicles which includes a function called a global positioning system (hereinafter referred to as a GPS) for determining the present position based on signals from satellites, and a function of searching and displaying map information in an optical disk for data storage (hereinafter referred to as a CD-ROM).
2. Description of the Prior Art
In a first conventional navigation apparatus for vehicles, as shown in FIG. 30, the main body of the navigation apparatus for vehicles consists of a GPS receiver R connected to a GPS antenna A, a CD unit CD for driving a CD-ROM containing map information, a display unit D for displaying a map, and an ECU for controlling the entire operation. When used in a car, the main body is mounted to a proper position within the interior of the car. When used outside the car, the main body is removed from the mounted position and is carried outside for use.
In a second conventional navigation apparatus for vehicles, as shown in FIG. 31, the main body of the navigation apparatus for vehicles consists of a GPS receiver R connected to a GPS antenna A, a gyro sensor J, a CD unit CD for driving a CD-ROM containing map information, a display unit D for displaying a map, and an ECU for controlling the entire operation, and is undetachably mounted to a proper position within the interior of a car.
In a third conventional navigation apparatus for vehicles (Japanese Patent Application Laid-Open (kokai) No. 7-14095), as shown in FIG. 32, the main body H of the navigation apparatus for vehicles, which includes a GPS receiver connected to a GPS antenna, a CD unit for driving a CD-ROM containing map information, a display unit D for displaying a map and an ECU for controlling the entire operation, is mounted on a stand S which sits upright on the floor of a car. In such a state, basic operations such as navigation, display of the current position, enlargement/reduction of a map, and writing a mark can be performed. However, when a route is preset so as to display an optimal route, the main body H of the navigation apparatus for vehicles must be removed from the stand S.
Since the first conventional navigation apparatus for vehicles neither includes a gyro within the apparatus, nor utilizes the traveling information of a vehicle, this apparatus has a problem of producing error in the current position.
Since the second conventional navigation apparatus for vehicles includes the gyro sensor J, error in the current position is hardly produced. However, this apparatus has the problems that the position and inclination of the apparatus must be maintained constant, and that the apparatus has an increased overall size and therefore is undetachably installed in the vehicle, thereby making it impossible to carry it.
Further, the third conventional navigation apparatus for vehicles has the problem that the setting of a route for displaying an optimal route cannot be performed unless the main body H of the navigation apparatus for vehicles is removed from the stand S.